This invention relates to sanitary napkins (or sanitary pads) used to absorb and hold menstrual discharges and more particularly to such sanitary napkins provided with wings and liquid barriers adapted to be folded back around a crotch zone of the user's shorts in order to fix the napkin thereto.
Conventional sanitary napkins classified herein for the purpose of explanation as napkins of a first type comprise a liquid-permeable topsheet, a liquid-impermeable backsheet, a liquid-absorbent core sandwiched therebetween, and wings formed by sections of the top- and backsheets which outwardly extend from laterally opposite side edges of the liquid-absorbent core at a longitudinally middle portion of the liquid-absorbent core. In actual use of napkins of this type, the wings are folded back onto the outer surface of a crotch zone of the user's shorts and thereby the wings are fixed thereto with adhesive applied to rear sides of the respective wings. Thus, the napkins are advantageous in that they can be reliably fixed to the crotch zone.
Well known sanitary napkins classified as napkins of a second type include liquid barriers longitudinally extending along laterally opposite sides and adapted to be raised under the effect of elastic elements associated with the respective liquid barriers. Napkins of this type are advantageous in that the liquid barriers effectively contribute to prevent body fluids from laterally leaking.
Sanitary napkins of prior art classified as napkins of a third type comprise an upper napkin and a lower napkin dimensioned wider than the upper napkin so that the former is fixed to the latter at longitudinally opposite ends of the latter. In using napkins of this type, the lower napkin is fixed to a crotch zone of the user's shorts with adhesive applied on a rear side of the lower napkin. Thus, such composite napkins are advantageous in that the upper napkin is free from any adverse influence of deformation possibly occurring in the crotch zone of the user's shorts.
However, the napkins of the first and third types are inferior to the napkins of the second type with respect to the preventive effect against lateral leakage of body fluids because both the napkins of the first type and the napkins of the third type have no liquid barriers characterizing the napkins of the second type. The napkins of the second type are, in turn, inferior to the napkins of the first type as far as fixation of the napkin to a crotch zone of the user's shorts is concerned. In view of this, we attempted to obtain sanitary napkins having combined advantageous features of these first and second types and found that the advantageous feature of the second type can not satisfactorily function when these two advantageous features are merely combined with one another.
More specifically, with such composite napkins of the prior art, the liquid barriers provided on the component napkin of the second type are pulled outward against the contractile force of the associated elastic members as the wings provided on the component napkin of the first type are fixed to the user's shorts by folding the wings back onto an outer side of the crotch zone thereof, with the disadvantageous consequence that the liquid barriers can not satisfactorily operate.
In view of these problems remaining unsolved in spite of various efforts which have been attempted by the prior art, it is a principal object of the invention to provide improved sanitary napkins maintaining the advantages expected from combination of the above-mentioned first, second and third types without loss of the respective advantages.